The Borystenitichus Discourse (Or. XXXVI) of Dio Chrysostom, a very elaborate rhetorical construction in which reality and fiction are mixed, raises the problematic relationship with Otherness. Borysthenes, despite its being a Greek colony, represents a point of contact with a liminal reality, where the boundaries between Greeks and Barbarians gets confused. This paper aims to analyze the ways and strategies through which the rhetorician represents himself in face of the complex reality of Borysthenes which shines through his interlocutors. The rhetorician appears at first well aware of his own superiority and reveals an attitude of intellectual colonization; but the dialectic context leads him to rectify both the contents and the rhetorical-argumentative strategies of his speech, finally arriving at the exposition of Stoic cosmology in a Zoroastrian frame within the two myths which Dio attributes directly to the Persian Magi.

Keywords: Greeks/Barbarians – Identity/Otherness – Intellectual colonization – Dialectical debate – Zoroastrian myths